Canine Ehrlichiosis: Clinical and Therapeutic Evaluation

Canine ehrlichiosis is an important tick-borne infectious disease of dogs caused mainly by Ehrlichia canis, an obligate intracellular bacterium that infects monocytes and macrophages. The disease is primarily transmitted by the brown dog tick, Rhipicephalus sanguineus, and occurs worldwide. Clinical manifestations range from subclinical infection to severe, life-threatening disease. Affected dogs commonly show fever, lethargy, anorexia, weight loss, lymphadenopathy, splenomegaly, epistaxis, and ocular abnormalities. Hematological alterations include thrombocytopenia, anemia, leukopenia or leukocytosis, and changes in lymphocyte counts. Chronic infections may cause bone marrow suppression leading to severe pancytopenia. Diagnosis involves clinical examination, hematological evaluation, and confirmatory laboratory tests. Ultrasonography may reveal abnormalities such as hepatomegaly, splenomegaly, and changes in liver, spleen, gall bladder, and urinary bladder. Treatment primarily involves doxycycline, which is considered the drug of choice against Ehrlichia canis. Rifampin also serves as an alternative therapeutic option with beneficial effects in affected dogs.